1. Field of the Invention
The present invention relates generally to methods and apparatus for installing sheet materials in buildings, and, more particularly, to methods and apparatus especially adapted for installing sheet materials on ceilings.
2. Description of the Prior Art
Installation of sheet materials in buildings is a common practice in the building trades. Of special difficulty is the installation of sheet materials on ceilings. Generally, installing materials, such as sheet rock, on ceilings requires two persons, one to hold the sheet material against the ceiling, and the other person to nail or screw the sheet material into secure attachment with the ceiling. In this respect, it would be desirable if a device were provided for installing sheet materials on a ceiling which does not require the labor of two persons, one to hold the sheet material in position and the other to secure the sheet material onto the ceiling.
When a person is required to hold a sheet material against the ceiling, the person often undergoes unpleasant stress and strain. Holding a heavy piece of sheet material above one's head is very fatiguing. Gravity is opposing both the raising of the lifter's hands and arms and the retaining of the sheet material against the ceiling. In this respect, it would be desirable if a device were provided for installing sheet materials on a ceiling which does not require a person to hold the weight of sheet material over his head prior to securing the sheet material to the ceiling.
Throughout the years, a number of innovations have been developed relating to installation of sheet materials on ceilings. The following U.S. patents are representative of some of those innovations: U.S. Pat. Nos. 3,871,477; 4,709,527; 4,733,844; and 4,928,916. More specifically, U.S. Pat. No. 3,871,477 discloses a large, complex, heavy, hydraulically operated and expensive sheetrock lift and scaffold. Such a large and heavy device is impractical also because it takes up great quantities of space in storage and transportation. In view of these undesirable features with this patent, it would be desirable if a device for aiding in the installation of sheetrock on a ceiling would be small, simple in operation and construction, lightweight, manually operated, and take up little space in storage and transportation.
U.S. Pat. No. 4,709,527 discloses a small, simple, lightweight, manually operated sheetrock hanging tool. A problem associated with this device is that, for a large piece of sheetrock, it appears that two persons must be involved in the installation. More specifically, the device in this patent is installed at the edge of a piece of sheetrock. A piece of sheetrock has its center of gravity located near the center of the piece of sheetrock. With a large piece of sheetrock, the center of the sheetrock is quite far from the edge of the piece. As such, quite a bit of leverage is created by gravity for the center of gravity around the edge of the sheetrock. This leverage of the center of gravity around the edge of the sheetrock makes it difficult for one person to install a large piece of sheetrock using the device shown in this patent. In this respect, it would be desirable if a device were provided for installing large pieces of sheet materials on a ceiling so that the fact that the center of gravity of the large piece is located quite a distance from the edge of the large piece would not prevent one person from installing the large piece on a ceiling.
Both U.S. Pat. Nos. 4,733,844 and 4,928,916 show similar devices for supporting sheetrock on a ceiling. The devices are in the form of adjustable height columns that are erected from floor to ceiling. These devices have the advantage of being usable by one person for a ceiling-mounted sheetrock installation. However, a number of disadvantages are also associated with these devices. To use these devices for supporting the sheetrock on the ceiling, the sheetrock must first be lifted to the ceiling in a horizontal orientation. It appears that these devices do not aid in the actual lifting of the sheetrock to the ceiling. In this respect, it would be desirable if a device were provided for installing sheet materials on a ceiling which facilitates lifting the sheet materials from floor level to the ceiling.
The devices disclosed in U.S. Pat. Nos. 4,733,844 and 4,928.916 have quite a large number of components connected to each other. There is a horizontal planar element that fits under the sheetrock. There are at least three mutually adjustable vertically oriented elements that enable a vertical height adjustment from floor to ceiling. The complexity of these devices stems from the fact that the sheetrock on the ceiling is supported by a floor-based support. In this respect it would be desirable if a device were provided for installing sheet materials on a ceiling which does not depend upon a floor-based support.
A floor-based support has another disadvantage. By the sheetrock support occupying space on the floor, a workers mobility on the floor is reduced for fear of bumping into the floor-based support and causing the sheetrock to fall from the ceiling. In this respect, it would be desirable if a device were provided for installing sheet materials on a ceiling which did not occupy floor space and did not impede a worker's movement on a floor for fear of knocking out a floor-based support for the sheetrock held against the ceiling.
In addition, U.S. Pat. No. 4,257,205 may be of interest for its disclosure of an attachment system for suspending drywall ceiling panels. This device is for permanent installation of the ceiling panels. In contrast, when a worker installs sheet materials on a ceiling, the worker wants to use installation aids that are used only temporarily. That is, the worker wants to use them for installation, but the worker does not want to leave them on the ceiling permanently. This certainly is not practical for installation aids that protrude from the ceiling and are clearly visible from the floor below when the installation devices are employed. In this respect, it would be desirable if a device were provided for installing sheet materials on a ceiling which were used on a temporary basis, just during installation, and are removed when installation is completed to be used over and over again.
Still other features would be desirable in an apparatus for installing sheet material on a ceiling. The apparatus itself should be easily installed and easily removed so that it can be easily reused. To suspend a relatively heavy piece of sheet material from a ceiling, the ceiling sheet installation apparatus should be capable of being secured strongly to a ceiling structure so it can adequately bear the weight of the sheet material.
Thus, while the foregoing body of prior art indicates it to be well known to use supports for supporting sheetrock against a ceiling, the prior art described above does not teach or suggest a ceiling sheet installation apparatus which has the following combination of desirable features: (1) does not require the labor of two persons, one to hold the sheet material in position and the other to secure the sheet material onto the ceiling; (2) does not require a person to hold the weight of sheet material over his head prior to securing the sheet material to the ceiling; (3) can be easily installed and easily removed so that it can be easily reused; (4) is small, simple in operation and construction, lightweight, manually operated, and takes up little space in storage and transportation; (5) provides for installing large pieces of sheet materials on a ceiling so that the fact that the center of gravity of the large piece is located quite a distance from the edge of the large piece does not prevent one person from installing the large piece on a ceiling by himself; (6) facilitates lifting the sheet materials from floor level to the ceiling; (7) does not depend upon a floor-based support; (8) does not impede a worker's movement on a floor for fear of hocking out a floor-based support for sheetrock held against the ceiling; (9) provides for installing sheet materials on a ceiling which are used on a temporary basis, just during installation, and are removed when installation is completed to be used over and over again; and (10) is capable of being secured strongly to a ceiling structure so it can adequately bear the weight of the sheet material. The foregoing desired characteristics are provided by the unique ceiling sheet installation apparatus of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.